Press Release
Forward-looking combination of refinement and environmental friendliness
- “DIESOTTO” – innovative drive concept for the future of the spark- ignition engine
- Active PRE-SCAN suspension raises comfort to entirely new levels
- SERVO-HMI: new communication between man and vehicle
Individual mobility requirements will continue to rise worldwide in the coming years, particularly in countries with emergent economies. Mobility will remain the most important foundation for the successful development of the economy and society in the future.
Mobility will change in character. More and more people live in huge cities; more time will be spent on the streets and roads every day. This raises the demand not only for economical automobiles, but also automobiles which are comfortable and relieve driver stress as well as being safe, of course. Moreover, mobility increasingly will be determined by limited resources and the duty to treat the natural foundations of life gently. Most of all, consumption and emissions will have to be cut further.
Making mobility sustainable and compatible with humans and the environment is a responsibility to which Mercedes-Benz as inventor of the automobile has a strong commitment. Engineering spirit and innovative power are crucial, for intensive R&D alone gives rise to new technologies and opens up ways to new solutions.
The research car tradition of Mercedes-Benz documents the resolve and foresight with which the engineers from Stuttgart long have been dealing with the core topics of automotive engineering, developing innovative solutions for the future.
The F 700 thus shows new ways to a highly comfortable and at the same time resource-conserving mobility:
- The forward-looking DIESOTTO drive reduces the fuel consumption of luxury-class sedans to the level of compact cars.
- The active PRE-SCAN suspension raises ride comfort to previously unattained levels.
- The interior concept and the operating concept with SERVO-HMI guarantee relaxed travel even over the longest distances.
The Mercedes-Benz F 700 thus redefines refined automobility.
The DIESOTTO drive: A gasoline engine as economical as a diesel
An automobile’s fuel consumption is determined by a great many factors. They include weight, air drag and rolling resistance (tires), or the management of the many energy consumers in a vehicle. But the central and most crucial factor of all is the drive system. Enhancing engine efficiency remains the primary and decisive factor in cutting fuel consumption.
Mercedes-Benz is convinced that in the coming years, internal combustion engines will remain the dominant type of drive in automobiles – albeit appreciably improved in all dimensions. Depending on operating conditions and use profile, supplementing it with a hybrid module can be a sensible step. Mercedes-Benz offers a wide array of gasoline and diesel engines which can be complemented with different hybrid modules in the near future. So depending on field of use and personal preferences, every customer can select the drive which is the optimum for his or her purposes.
Until now gasoline and diesel engines have had clearly distributed roles: the diesel was more economical, but emission control was easier to manage in the gasoline-powered car. “Our strategic objective is to make the gasoline-powered car as economical as the diesel, and the diesel as clean as the gasoline engine,” says Dr. Thomas Weber, Board member of DaimlerChrysler AG responsible for Group Research & Mercedes Car Group Development. One part of this strategy already has been implemented: the BLUETEC technology, which reduces nitrogen oxide emissions, gives the diesel engine the capacity to comply even with the world’s harshest emission standards – including those to come in future. BLUETEC is already on the market in the and will be available in from the end of 2007.
“Researchers and developers need challenges and great goals,” says Dr. Thomas Weber. “For this reason we think much farther ahead at Mercedes-Benz: we are going to combine the strengths and advantages of both combustion principles in one innovative engine concept. The DIESOTTO drive is a major step forward.”
Unique system for reducing consumption
The DIESOTTO drive in the new research car is a unique, integrated system for consumption reduction.
It involves
- downsizing by reducing cylinder size and smaller displacement;
- turbocharging;
- direct gasoline injection;
- variable valve control;
- controlled auto ignition (CAI);
- hybrid module with integral starter-generator.
DIESOTTO brings the benefits of diesel technology to the gasoline engine: in the CAI mode the air-fuel mixture ignites itself the same as in a diesel engine. And yet DIESOTTO makes no special demands on fuel quality: the engine runs on normal gasoline.
Controlled auto ignition, moreover, not only is more economical than the conventional combustion triggered by a sparkplug, it is also cleaner as regards emissions. In controlled auto ignition, as the Mercedes-Benz engineers term their new process, hardly any nitrogen oxides (NOx) are produced. DIESOTTO thus points to the future of the gasoline engine – a future imagined, researched and developed by Mercedes-Benz.
Two-stage charging and hybrid module
The first step to less consumption is to downsize the engine. Instead of a big-volume, naturally aspirated engine, a compact, turbocharged power plant is used. This leap backwards in cylinder size and displacement reduces internal friction in the engine. The smaller unit increasingly runs in a more efficient combustion range. The drive system in the research car is a four-cylinder with a displacement of a mere 1.8 liters. At first, this is somewhat of a surprise for a vehicle of the luxury class, where up to now at least six cylinders and three liters displacement are the standard.
The sensation of effortlessly superior driving in the luxury class nonetheless is retained. The DIESOTTO drive gets additional power from a two-stage turbocharger system. A larger low-pressure turbocharger and a high-pressure turbocharger of smaller diameter are connected in series and together optimally cover the complete engine speed range. The complex system makes for good responsiveness from low revs, provides high torque and pulling power and delivers high peak output. For driving off, the internal combustion engine additionally gets assistance from the electric motor of the hybrid module.
The maximum output of the internal combustion engine is 175 kW (238 hp); the electric motor develops another 15 kW (20 hp); the maximum torque of the system is impressive 400 Newton meters. This guarantees performance commensurate with the luxury class, as the time of 7.5 seconds for the 0 to 100 km/h (62 mph) sprint documents.
The hybrid module with its integral starter-generator helps to even further reduce the excellent fuel consumption mainly in urban stop-and-go operation. The internal combustion engine always is shut off when it is not needed. On moving off, the combination of internal combustion engine and torquey electric motor is a tandem that ensures a powerful but silky smooth start. Besides that, during coasting and braking the electric motor recovers energy which is stored in a special high-voltage battery and used for the next starting operation. This starter-generator is integrated in the housing of the 7G-TRONIC automatic transmission.
